Omega-3 Fatty Acids in Preventing Breast Cancer in Women at High Risk of Developing Breast Cancer

DISEASE CHARACTERISTICS: At increased risk of developing breast cancer, as defined by 1 of the following criteria: 5-year Gail risk ≥ 1.7% Calculated 5-year Gail risk ≥ 5 times the average for age group, as defined by 1 of the following: At least 0.1% (for patients age 20-29) At least 1.0% (for patients age 30-39) At least 1.7% (for patients age 40 and over) Known BRCA1 or BRCA2 mutation carrier Family history consistent with hereditary breast cancer, as defined by any of the following: At least 4 relatives diagnosed with breast cancer at any age At least 2 first-degree relatives diagnosed with breast cancer at age 50 or younger Breast and ovarian cancer diagnosed in the same relative At least 2 occurrences of breast cancer and 1 occurrence of ovarian cancer at any age in the same family Atypical hyperplasia or lobular carcinoma in situ of the breast by prior biopsy History of unilateral ductal carcinoma in situ of the breast History of invasive stage I breast cancer in remission (completed local and systemic standard therapy) History of ovarian cancer in remission for > 5 years Baseline mammogram performed within the past 6 months with an interpretation of not suspicious for malignancy (BIRAD 1-3) Not eligible for OR refused standard breast cancer risk reduction strategies (e.g., prophylactic oophorectomy, prophylactic mastectomy, or tamoxifen) PATIENT CHARACTERISTICS: Age 18 and over Sex Female Menopausal status Not specified Performance status SWOG 0-1 Life expectancy Not specified Hematopoietic Absolute granulocyte count ≥ 1,500/mm^3 Platelet count ≥ 100,000/mm^3 Hemoglobin ≥ 8.0 g/dL Hepatic SGOT and/or SGPT ≤ 2.5 times upper limit of normal (ULN) Alkaline phosphatase ≤ 2.5 times ULN Bilirubin ≤ 2.0 times ULN Renal Creatinine ≤ 2.0 mg/dL Other Not pregnant or nursing Negative pregnancy test No underlying medical, psychiatric, or social condition that would preclude study participation No other invasive malignancy within the past 5 years except nonmelanoma skin cancer PRIOR CONCURRENT THERAPY: Biologic therapy Not specified Chemotherapy Not specified Endocrine therapy More than 6 months since prior and no concurrent hormonal therapy, including any of the following: Antiestrogens Estrogen Selective estrogen-receptor modulators Progestins Aromatase inhibitors Hormonal contraceptives Radiotherapy Not specified Surgery No prior bilateral mastectomy Other More than 3 months since prior and no concurrent chronic (i.e., > 3 times per week) non-steroidal anti-inflammatory drugs (e.g., aspirin, ibuprofen, or indomethacin) or cyclooxygenase-2 inhibitors No prior cancer treatment that would preclude study treatment